Tearle R G, Chen T, Brien F D
Davies Research Livestock Centre, School of Animal and Veterinary Sciences, University of Adelaide, Roseworthy, South Australia, Australia.
Anim Genet. 2025 Feb;56(1):e13495. doi: 10.1111/age.13495. Epub 2024 Nov 28.
Sheep have naturally pigmented wool which interferes with dyeing. Selection has been carried out over many years to remove pigment, with substantial success, but most wool still contains some pigment. As an alternative to selection, it has been proposed to take a naturally occurring mutation found in black Suffolk sheep, that blocks wool pigmentation, and introgress it into other breeds. However, the nature of the mutation has not been identified, prompting us to characterise it. The Suffolk white-fleece phenotype is associated with a novel 3-bp deletion in the gene SLC45A2, which encodes a membrane bound transporter that mediates melanin synthesis. The deletion results in the removal of one amino acid from the protein. The assignment of this deletion as the likely causative mutation is supported by it: being homozygous in the genome of nine animals with a white fleece and not homozygous in the genomes of eight animals with a black fleece; having a high level of conservation of the encoded amino acid sequence in the region surrounding the deleted amino acid across Mammalia; and the same deletion (but in a compound heterozygous state) being found in human SLC45A2 in a person with albinism.
绵羊的羊毛天然带有色素，这会干扰染色过程。多年来人们一直在进行选育以去除色素，并且取得了显著成效，但大多数羊毛仍含有一些色素。作为选育的替代方法，有人提议利用在黑色萨福克绵羊中发现的一种自然发生的突变，该突变可阻止羊毛色素沉着，并将其导入其他品种。然而，这种突变的本质尚未确定，这促使我们对其进行表征。萨福克白色羊毛表型与基因SLC45A2中一个新的3碱基缺失有关，该基因编码一种介导黑色素合成的膜结合转运蛋白。这种缺失导致蛋白质中一个氨基酸的缺失。将这种缺失认定为可能的致病突变有以下依据：在九只白色羊毛动物的基因组中是纯合的，而在八只黑色羊毛动物的基因组中不是纯合的；在哺乳动物中，缺失氨基酸周围区域的编码氨基酸序列具有高度保守性；并且在一名白化病患者的人类SLC45A2中也发现了相同的缺失（但处于复合杂合状态）。
